Hydraulic bolting systems – keeping components aligned

Hydraulic bolting systems offer industry optimum outcomes for motor and gearbox alignment. Alan Johnson reports.

Electric motors and gearboxes can operate together for significant periods of time with few reliability issues, however, if they are poorly mounted or misaligned, serious and often costly problems can occur very quickly.

Having the motors and gearboxes poorly mounted or misaligned can cause problems such as bearing and seal breakdown, coupling failure and possible consequential damage to other components.

The problem often occurs when components are assembled or replaced in working environments where there is urgency to recommission the machinery, especially when drive motors and gearboxes are swapped out with replacements which may have some differences in mounting hardware, or originate from different manufacturers.

John Bucknell, CEO and Founder of Australian hydraulic fastening company Technofast Industries, explains that the correct alignment of electric motors and gearboxes is always required when changing one or the other. 

“Large machines are often aligned using laser equipment to ensure best outcomes, with the procedure normally requiring linear adjustment and shim packing for correct height alignment.”

After each alignment adjustment, the mounting bolts must be tightened and the alignment measured to assess the outcome. This may require a number of passes to get the required result and often takes many hours of labour and downtime.

Bucknell says the use of his company’s EziTite hydraulic bolts/nuts can dramatically reduce installation times as the mounting bolts/nuts do not have to be screwed down and fully tightened repeatedly with torque wrenches or other means.

When used in conjunction with the correct alignment tooling, the hydraulic nuts and bolts allow the operator to bring all corners of the electric motor or gearbox down simultaneously for measurement of alignment. 

Necessary linear adjustments or shim packing can be done by quickly releasing the hydraulic pressure, making changes, then reapplying it to achieve the optimum result. 

“When all is to spec, the EziTite’s lock ring is simply nipped up tight, the pressure released and pressurizing equipment removed from the finished job. 

The whole process takes just minutes, not hours.”

Hydraulic nuts/bolts

Bucknell says hydraulic nuts and bolts are also ideal for simultaneously tensioning bolting arrays such as fasteners on a flange, joint or cover, often loading 100 per cent of the fasteners at once.

“This gives an extremely accurate even load onto the bolted joint, ensuring a leak-free start-up.”

He says the use of the hydraulic nuts and bolts offer the user additional benefits including improved safety, by removing flogging spanners and larger wrenches, along with greater accuracy and much reduced downtime on vital equipment.

“Plus of course there is minimal physical effort required to operate hydraulic bolting systems. Even in tight spaces, as long as you can connect the pressure hose you can tighten the bolt,” Bucknell added.

He explained that the hydraulic nuts and bolts can be specified and manufactured using high strength alloy or stainless steels to suit application requirements, with protective covers or optional surface treatments available.

The hydraulic bolts are precision engineered, high performance, hydraulically operated fasteners which incorporate mechanisms for tensioning. They can be easily fitted using standard pumping equipment such as hand operated, electric hydraulic or air hydraulic pumps.

The company’s hydraulic nuts can be rapidly applied by being installed on bolt studs then hydraulically actuated, stretching the bolt to the precise tension required and then locking it in place mechanically with a locking device. 

The reverse procedure permits equally rapid disassembly when it is eventually required for maintenance, for example. 

The hydraulic nuts and bolts are said to be ideal where accurate and reliable loading is required on bolting, where vibrational or torsional stresses are a problem, and regular maintenance requires repeated adjustment or removal of nuts. They are also suitable for confined or difficult nut locations.

Standard range of the EziTite hydraulic bolt is 20mm to 100mm diameter and features a unique lock-ring thread technology to ensure maximum retained load and a spherical seat ensures correct alignment to the joint face.

Available in a variety of seal designs for temperature/pressure requirements, the maximum pressure of EziTite hydraulic bolts is 100MPA, though custom designs may be higher.